'Body builders' begin growing organs

STOCKHOLM - Andemariam Beyene sat by the hospital window, the sun on his face, and talked about when he thought he would die.

STOCKHOLM - Andemariam Beyene sat by the hospital window, the sun on his face, and talked about when he thought he would die.

Two and a half years ago, doctors in Iceland, where Beyene was studying to be an engineer, discovered a golf-ball-size tumor growing into his windpipe. Despite surgery and radiation, it kept growing. In the spring of 2011, when Beyene came to Sweden to see another doctor, he was practically out of options. "I was almost dead," he said. "There was suffering. A lot of suffering."

But the doctor, Paolo Macchiarini, at the Karolinska Institute here, had a radical idea. He wanted to make Beyene a new windpipe, out of plastic and his own cells.

Implanting such a "bioartificial" organ would be a first-of-its-kind procedure for the field of regenerative medicine, which for decades has been promising a future of ready-made replacement organs - livers, kidneys, even hearts - built in the laboratory.

For the most part that future has remained a science-fiction fantasy. Now, however, researchers such as Macchiarini are building organs by using the body's cells and letting the body itself do most of the work.

"The human body is so beautiful, I'm convinced we must use it in the most proper way," said Macchiarini, who runs a laboratory that is a leader in the field, also called tissue engineering.

So far, only a few organs have been made and transplanted, and they are relatively simple, hollow ones - such as bladders and Beyene's windpipe, which was implanted in June 2011. But scientists around the world are using similar techniques with the goal of building more-complex organs. At Wake Forest University in North Carolina, where the bladders were developed, researchers are working on kidneys, livers and more. Labs in China and the Netherlands are among many working on blood vessels.

This work is far different from the efforts that produced artificial hearts decades ago. Those devices are sophisticated machines, but in the end they are only that: machines.

Tissue engineers aim to produce something that is more human. They want to make organs with the cells, blood vessels and nerves to become a living, functioning part of the body. Some, such as Macchiarini, want to go even further - to harness the body's repair mechanisms so that it can remake a damaged organ on its own.

Researchers are making use of advances in knowledge of stem cells, basic cells that can be transformed into types that are specific to tissues like liver or lung. They are learning more about what they call scaffolds, compounds that act like mortar to hold cells in their proper place and that also play a major role in how cells are recruited for tissue repair.

Tissue engineers caution that the creation of complex organs is still a long way off. But they are increasingly optimistic.

"Over 27 years, I've become more convinced that this is doable," said Dr. Joseph P. Vacanti, a director of the Laboratory for Tissue Engineering and Organ Fabrication at Massachusetts General Hospital and a pioneer in the field.

In Beyene's case, an exact copy of his windpipe was made from a porous, fibrous plastic, which was then seeded with stem cells harvested from his bone marrow. After a day and a half in a bioreactor - a kind of incubator in which the windpipe was spun in a nutrient solution - the implant was stitched into Beyene, replacing his cancerous windpipe.

Now, 15 months after the operation, Beyene, 39, who is from Eritrea, is tumor-free and breathing normally. In Stockholm earlier this year for a follow-up visit, he showed the long vertical scar on his chest and spoke quietly in English.